EUR 5A FAQs
HIGH TEMPERATURE LIMIT SENSOR
THE CONTROLLER IS OSCILLATING – HOW DO I FIX THIS?
Disconnect Equipment Ground terminal (18).
The EUR–5A sensor circuits and the EMC inputs are referenced to a common circuit ground. In most situations, this part of the system can be left floating from the building panel ground (not connected to it). In some cases, noise or transient immunity may be improved if the EUR–5A (with its sensors) is actually grounded to the building ground. But this can create a voltage difference on the sensors because of the difference in the electrical potential of the building ground and the outdoor building structures contacting the sensors creating a ground loop. To avoid this potential ground loop install a resistor, such as 100 ohms, between the EUR–5A ground terminal (18 or 19) and the building panel ground.
WHAT ARE THE BEMC CONNECTIONS FOR?
These connections are made to pins 10 through 16. The following diagram will aid in making these connections. See page 9 of EUR-5A manual.
ENERGY MANAGEMENT COMPUTER INTERFACE
The EUR–5A provides three contact-closure outputs to the EMC to indicate operational status with indications of Supply Present, Snow Present, and Heat On. See Figure 11.
These floating relay contacts share a common connection (terminal 13).
• The SUPPLY PRESENT terminal (14) connects to the common terminal (13) when the EUR–5A is receiving 24-volt power.
• The SNOW PRESENT terminal (15) connects to the common terminal (13) when the sensors report the presence of ice or snow.
• The HEATER ON terminal (16) connects to the common terminal (13) while the heaters are on.
When connecting to ECM connect as follows:
• OVERRIDE ON: when the ECM connects terminals 10 and 11 this forces the heaters to be on.
• OVERRIDE OFF: when the ECM connects terminals 10 and 12 this forces the heaters to be off.
These functions are independent of weather conditions and the status of the hold-on timer. If both are engaged, OVERRIDE OFF prevails.
IS THERE A WAY TO MAKE THE SYSTEM COME ON WITH TEMPERATURE ONLY?
If you must do so choose a thermostat with dry contacts that close when the temperature is below 40F and connect it to the override-on terminals of the EMC section of the terminal block.
CAN I SIMULATE A SENSOR CALL FOR HEAT TO TEST THE SYSTEM?
WHEN THE SYSTEM WAS INSTALLED THE HIGH TEMPERATURE SENSOR WAS NOT INSTALLED, CAN I STILL MAKE THE UNIT WORK?
In roof and gutter applications the sensor is run outside the building and placed in a location that is out of direct sunlight and away from other heat sources such as air conditioners or vents.
HIGH TEMPERATURE LIMIT SENSOR
The High Temperature limit sensor is connected across terminals 1 and 2. There is no polarity requirement. See Figure 9.
If the High Temperature limit sensor is not used, then a 470k ohm resistor must be connected in its place, across terminals 1 and 2 of the EUR–5A. This is necessary to allow the EUR–5A to operate without the sensor. If the circuit is left open, the Heat indicator on the EUR–5A panel will flash.
WHY DOESN’T ADJUSTING THE HIGH TEMPERATURE LIMIT DIAL TURN THE UNIT ON?
HIGH TEMPERATURE LIMIT
Sets maximum temperature from 40°F to 90°F (4°C to 32°C).When that temperature is reached, the heat will always be turned off.
Team ETI has been on a whirlwind trip around the globe while spreading the benefits of the ETI product line. In late January, we attended the World of Concrete show in Las Vegas, Nevada. Less than a week later our team was headed off to the far east to attend the Convergence India trade show in New Delhi, India.
Chad Griffin, ETI Director of Sales & Marketing (right), along with Jeremy Crawford, ETI Business Development Representative assisted our strategic business partner’s, Optimum Viking Satcom, by explaining the value and benefits of adding the ETI product line to Southeast Asia telecom & SATCOM infrastructure.
Next, you’ll be able to catch up with the Team ETI at:
NAB ( National Association of Broadcasters )
April 8th – 11th
Las Vegas Convention Center
Las Vegas, NV
April 24th & 25th
Montréal, Québec Canada
If you’re planning to attend either of these shows and would like more information about ETI, our line of environmental controls products and the added value they bring, our team would cherish the opportunity to meet with you and your team at either or both shows.
For the last four days, the ETI Snow Switch Team has been showcasing the newest addition to the Snow Switch product line, the Snow Switch CIT-2, at the World of Concrete convention in Las Vegas, NV.
In addition to the revolutionary design of the CIT-2, what attendees of the World of Concrete were most impressed with is what the unit offers straight out of the box combined.
One of the best features of the Snow Switch CIT-2 is that for the first time in ETI’s 50 year history of engineering snow & ice melt solutions, this is the first unit to be designed specifically to work with the complete line of ETI Snow Switch controllers, as well as, any other comparable unit on the market, or even as a stand-alone unit.
That’s not just groundbreaking, it’s revolutionary.
Click the button below for more information about the Snow Switch CIT-2 Aerial Snow Sensor.
ETI proudly introduces the SNOW SWITCH® CIT-2 Aerial Snow Sensor for surface snow and ice management systems.
The CIT-2 is designed to work with a controller or contactor, optimizing energy usage in heated snow/ice melting applications. The CIT-2 is also an excellent solution for building automation applications.
During dry or warm weather, the system’s heaters are turned off to save energy costs. The heaters are turned on only when snow and/ or ice is present, and kept on only long enough to ensure complete melting and drying. Temperature and time parameters can be varied within the CIT-2, enhancing system performance in a given environment and application.
- Automatic snow sensor for reduced energy consumption in sidewalk, gutter/downspout snow and ice melting applications
- Slim design minimizes visual impact
- Mounts on 3⁄4” PVC conduit for easy installation
- Operates on safe low voltage power
- Simple four wire connections: 2 for power, 1 for signal output
- Wire colors match commonly available cable for easier installation
- Convenient power-on self-test to verify proper sensor
- Made with UV-tolerant and corrosion-resistant materials for
- MADE IN THE U.S.A.
SNOW SWITCH CIT-2 | SPECIFICATIONS
24V AC 50/60Hz, 24V DC, or 24V full wave rectified AC/ pulsed DC 0.2A max
Relay contacts: 2A max, 30V.
|SET POINT TEMPERATURE||
|MINIMUM OPERATING TEMPERATURE||
Selectable -20°F, -15°F, -10°F or disabled for extremely
Set 1 hour
33⁄4 inches tall, 13⁄4 inches diameter
|STORAGE TEMPERATURE||-40°C to +85°C|
Can be mounted 500 feet from the controller using 22ga cable or up to 1,000 ft. using 18ga cable (Depending on load requirements)
February 20th , 2018 (SOUTH BEND, INDIANA) — Ben and Kerri Crawford are excited to announce the acquisition of Environmental Technology Inc. (ETI) located in South Bend Indiana. Born and raised in South Bend, Ben is excited to be back in the area and work in his hometown. When asked, Mr. Crawford said,” It’s great to have a presence where I started my career in Manufacturing 24 years ago. The team at ETI is strong and has an excellent reputation advancing engineered products for snow/ice management, heat tracing and telecommunications reliability and makes me proud to be a part of this industry.”
Ben Crawford has over twenty-four years of manufacturing experience as a C-Suite Executive of Industrial Operations. Ben’s strengths include strategic planning and deployment, global business development, key metric management and continuous improvement objectives.
Kerri Crawford has over sixteen years of entrepreneur experience as the Founder, President and CEO of a successful Indiana based small business in the Commercial Lending Industry. Kerri manages the daily operations and is heavily involved with the strategic vision of the company. Over twenty-two years of commercial lending experience and a dedicated employee focus have been the driving force behind her vision and the company’s success the past sixteen years.
When asked about the future of ETI the Crawford’s indicated, “We remain committed to our customers, vendors, and employees.” “We are excited to assist in growing the business, expanding the product line and working closely with the management team.” They went on to say, “The Jones Family for the past fifty years have built a wonderful company and we are honored to be able to continue ETI’s legacy into the future.”
Launched in 1968, Environmental Technology, Inc. designs and manufactures products for effectively managing the environment. From energy efficient snow melting and deicing to pressurization systems for satellite and microwave transmission lines. ETI has fifty years of experience as an industry leader in developing and delivering effective environmental management systems. Environmental Technology, Inc. has the experience you can count on.
For more information on our products go to https://networketi.com/
For media inquiries, please contact:
Chad Griffin, Director-Marketing Environmental Technology Inc.
How to avoid Snow and ice falling from buildings.
Sheets of snow and ice falling and being blown off buildings are a major hazard that can cause damage to the structure, equipment, and possibly injure someone. Winter conditions have been accounted for in the building design process for a long time, but mostly in a way that only accounts for the weight of the snow and ice acumination and how it will affect the building’s structure. New technologies, innovations, and design trends are requiring that more attention be paid to the dangers of snow and ice when designing and maintaining a building.
Before energy conservation was a big concern buildings were basically large boxes with inefficient insolation that would leak phenomenal amounts of heat that would melt most of the snow and ice almost immediately. Most older building also had simpler designs with smooth walls, and a flat roof with a tall parapet on top to contain snow and ice accumulation so it can be safely drained away. The only real concern back then was how much snow weight could the structure hold, and there were building codes and regulations to account for this.
With advancements in technology, materials, and engineering, buildings are vastly more energy efficient, retaining almost all their heat which creates a colder exterior for snow and ice to accumulate on. Some of these new materials create smooth surfaces snow and ice can slide down in an uncontrolled way causing hazards below. These new materials also allow for more complex building designs, which can create areas where snow and ice can accumulate in unforeseen dangerous ways. These advancements in technologies, materials, and building designs have immense benefits, but also create new problems and hazards which need to be addressed.
The most cost-effective way to address these hazards is in the design phase of the building. There are microclimate professionals that can take data such as local historic weather conditions, surrounding buildings, the building’s airflow patterns, shadow patterns, along with other factors and help identify any potential environmental problems with a building’s design before it is built. These microclimate professionals can also recreate designs in test conditions to see how they perform. It is highly recommended to consult a microclimate professional when designing a building to address potential hazards before the building is built and more expensive fix must be made.
Older buildings will still need to address this problem as they are constantly being upgraded to be more efficient and new buildings being built around them impacting their microclimate. This is where a snow and ice melt system should be installed for safety. Snow and ice acumination that forms in new ways on a building can cause unforeseen consequences. Water can freeze between and behind structures, expanding and causing structural damage. Drainage paths can be overwhelmed in some areas, causing refreezing and accumulation. New areas can become shaded by new buildings in the area causing accumulation where there wasn’t before that needs to be addressed and properly removed. A snow and ice melt system can increase the safety and protection of a building by minimizing the amount of accumulation and keeping drainage paths clear.
Preventing snow and ice buildup is important for the safety of a buildings structure, equipment, and the safety of people below. Whether it is in the design process, or after it is built a building needs to be able to manage snow and ice effectively. Any building’s microclimate should be periodically checked and analyzed to identify and address any problems, especially when they can impact the safety of the people below.
Click Here to view ETI’s Heat Trace and Snow and Ice Melt controls.
Many industries that use hoppers utilize heat trace to aid in material flow. Hoppers are elevated storage containers that contain and dispense granular materials. Commonly used in agriculture hoppers are also used in industries such as plastics, chemical, pharmaceutical, energy, and construction. Despite being used to hold and dispense different types of materials they all function the same way and face the same issues.
The main issues with hoppers focus on the material flow. These issues include aspects related to material sticking together or accumulating on the walls of the hopper. This is commonly caused by the particle structure of the material or the presence of moisture. There are many ways moisture can enter the system, these can be caused by environmental conditions or by water or chemicals being applied to the material in the process before being placed in the hopper.
Major environmental factors that can introduce moisture into the hopper material are temperature and humidity. One way to mitigate this is to install a heat trace system onto the hopper. This controls the temperature of the hopper and material avoiding drastic temperature differences which could cause condensation to form on the inside of the hopper.
The application of water or chemicals to the material or the hopper for dust prevention, cleaning or as a step in the production process add moisture to the material. Moisture such as this should be accounted for in the design and selection of a hopper system to insure proper flow. However, despite accounting for this added moisture in the system variable conditions can still cause flow problems. One major problem for hoppers with chemicals or water added is freezing. Material freezing in a hopper can cause the material to clump together or freeze to the walls, causing a blockage or flow problems. This can cause production to be shut down until the material can be thawed or it is manually cleared out. The presence of a heat trace system in these cases will avoid the freezing and allow the material to flow in a predictable manner, avoiding costly shutdowns or disruptions.
There are many pieces of equipment that can be added to a hopper system to aid in the material’s flow such as augers and vibration units, but to combat the effects of variable environmental impacts a heat trace system should be included.
Click Here to check out ETI’s Tracon Heat Trace controls.
Visit us at the 2018 NAB Show in Las Vegas, April 9th through the 12th. ETI will be presenting at the Viking Satcom booth #OE11045. Come out and see our ADH NETCOM and NETCOM NEMA on display and talk with ETI’s Dennis Sizemore and Chuck Gartland. Please contact your sales representative in advance to reserve a time to meet by
emailing email@example.com, or calling (574) 233-1202.
Thank you and we look forward to seeing you there.
While at the NAB journey through 1,700 Exhibitors within the Las Vegas Convention Center. From established, global brands to up-and-coming innovators, this collection of ground-breaking tools and solutions are set to form the next generation of storytelling.
Stop by and enter to win a Yeti cooler from ETI and Viking Satcom.
Satellite antennas radiate signal energy in distinct patterns that are reported as their radiation pattern envelope. These patterns consist of lobes which indicate the intensity of signal radiation radially on a horizontal plane emanating from the antenna. These patterns of signal strength are measured including both horizontal and vertical polarizations at three frequencies which represent the bottom, middle and top of the antenna’s band.
When the radiation signal strength is measured, a main lobe will indicate the main direction of the signal beam. This main lobe indicates the direction the signal will be effectively transmitted. The size of the lobes representing the strength of the signal will decrease as they get further from the main beam. Side lobes appear as small surges in signal radiation adjacent to the main beam. These side lobes can result in unwanted signal noise which can also reduce the antenna’s carrier signal.
The signal capacity of an antenna can be determined by dividing its carrier signal strength by its signal noise. Better antennas produce a better signal by creating minimal side lobes which reduces signal noise and increases the signal capacity. Antennas of lesser quality which have larger side lobes which diminish the antenna’s signal capacity. There are however ways improve an antenna’s signal capacity.
There are two main approaches to increasing an antenna’s signal capacity, increasing the carrier signal strength by increasing the transmission power, or by decreasing the signal noise. Increasing an antenna’s transmission power seems like an obvious solution, but it comes with added energy costs, and might not be applicable due to increased interference, regulatory restraints, and infrastructure limitations. Another way to increase the signal strength is to install a larger antenna, but installing a larger antenna is expensive, requires more maintenance, power, and a larger infrastructure. When increasing signal strength is too costly or not applicable decreasing the signal noise is an option. Simply realigning the antenna creating a different link path can drastically improve an antenna’s signal capacity, this is a low-cost way to decrease signal noise. The best solution would be to purchase an antenna that produces small side lobes. These are higher quality antennas that produce less signal noise resulting in a more optimized signal capacity.
Consulting an antenna’s radiation pattern envelope is important for selecting the right antenna for an application and important in designing and installing a communications system. Antenna manufactures publish radiation pattern envelope information for their products and make them available for review. When selecting, designing, installing, optimizing or troubleshooting an antenna or communications system always consider the antenna’s signal capacity by reviewing its radiation pattern envelope.
Heat Trace with Plastic Pipes
Heat cable can be used on plastic pipes but the plastic’s durability and thermal properties must be considered. Plastic has approximately 125 times the thermal resistance than steel but is also more susceptible to damage from direct high temperatures. The key to heating plastic pipes is to use a lower temperature and distribute it as evenly as possible.
It is always a good idea to use a heat trace system with an automatic thermostat and control, but especially so when using heat trace on plastic pipe. An automatic heat trace control can monitor and maintain the system’s temperature, alarm for problems, and shut off the heat cable to prevent damage.
There is heat cable designed specifically for plastic pipes that is self-regulating and has limited wattage. Self-regulating heat cables have a conductive core between two bus wires that becomes more conductive when cold. This system increases the power to the cold spots and decreases it to the warmer areas, which provides a more even heat source.
The manufacture of the plastic pipe should be able to provide information as to the maximum temperature and how close heat cable can be spaced or wrapped on the pipe to avoid damage. Some applications may require heat cable to be applied to opposite sides of the pipe at a lower temperature to distribute the heat more evenly, avoiding one direct area of concentrates heat which may damage the pipe.
It is recommended to install a foil material between the pipe and the heat cable to avoid direct contact and help provide a more even heating. If doing this place the heat trace control thermostat directly onto the pipe with no foil over it or between it and the pipe to ensure a more accurate reading.
You can use heat cable on plastic pipes as long as you follow precautions, such as determining your pipe’s thermal capacities, selecting a self-regulating, low wattage heat cable and using an automatic heat trace control with safety functions. Following these guidelines will help prevent damage and increase the life of your heat trace system.
Considering environmental impacts of snow and ice melt maintenance.
There are environmental costs involved with any snow and ice melt system, knowing and assessing these environmental costs can help you choose the snow and Ice maintenance system that will work best for your needs and environmental conditions.
Electric or hydronic snow and ice melt systems
Electric and hydronic snow and ice melt systems can be a large investment but offer a cleaner, complete, uniform melt that can be easily monitored and controlled automatically or manually. With electric and hydronic melt systems, the only environmental impact is from the energy used to heat the heater cables or fluid in the heating pipes. Modern snow and ice melt controls implement energy-saving technologies that can help reduce their operating cost and environmental impact.
Electric and hydronic melt systems also can consistently heat places where chemical snow and ice deicers would be damaging or impractical, such as on roofs and in gutters.
Chemical deicers are very common. They are versatile, require no initial setup or permanent installation and can easily be regulated and modified. However, there are several drawbacks to using chemical deicers. Chemical deicers can be corrosive and can impact the environment through runoff, absorption, and air transportation.
Chemical deicers are divided into three main types, chloride-based deicers, acetate-based deicers, and carbohydrates.
Chloride-based deicers, commonly known as salt deicers, are composed of Chloride (an anion) and either sodium, magnesium, or calcium (a cation). When chloride-based deicers dissolve, the anion and cation dissociate impacting the environment in different ways.
Chloride is corrosive, meaning it can deteriorate a material by chemical reactions. Chloride does not biodegrade or absorb into material easily, so it can accumulate changing the fertility and acidity of the soil, damage plant life, and enter ground and surface water.
Sodium, magnesium, and calcium effect soil and plant life differently. Sodium changes the structure of the soil, decreasing permeability, and infiltration. Sodium also increases the alkalinity of the soil, which reduces the magnesium, calcium, and other nutrients for plant life. Magnesium and calcium can be good for the soil and plant life by adding nutrients. Sodium reduces the hardness of water, again reducing the magnesium, calcium, and other nutrients and metals. Magnesium and calcium increase water’s hardness (increases mineral content), they can also decrease the toxicity of heavy metals in the water.
Acetate-based deicers, sometimes referred to as pet-safe deicers are less corrosive and are not as toxic to plants and wildlife than chloride-based deicers and. The most common type of acetate deicer is calcium-magnesium acetate, otherwise known as CMA. The characteristics of CMA indicate that it is mostly absorbed by soil surface, minimizing the amount that would be carried away by runoff to surface water or enter ground-water.
Since most of the acetate-based deicer runoff is absorbed by soil only a limited amount enters the water system where it’s effects can be minimized by dilution, larger moving bodies of water will be affected less than small stagnant bodies of water. When it does enter a water system in large enough concentration it increases the biological oxygen demand on rivers and lakes, creating a potential threat to aquatic life.
Carbohydrate-based deicers do not melt snow and ice, they reduce the reduce the freezing point of ice further than Chloride-based deicers, and can help deicers better stick to the surface. Carbohydrate-based deicers are relatively safe for the environment, except they do pose a similar increase in biological oxygen in lakes and rivers as acetate-based deicers. Carbohydrate-based deicers can also be used with chloride-based deicers to mitigate their corrosive nature.
Desiccant vs Membrane Dehydration. Two of the main types of dehydrators are used for waveguide dehydrators, desiccant dryers, and membrane dehydrators. Both effectively remove moisture from the air but do it in vastly different ways.
A waveguide is a tube-like structure that allows for the guided flow of electromagnetic waves with minimal energy loss. The waveguide must be clean and free of debris and humidity, because these can distort the wave, negatively impacting signal quality.
Waveguide dehydrators are commonly used to pump clean dry air into the waveguide to reduce the humidity. Two of the main types of dehydrators are used for waveguide dehydrators, desiccant dryers and membrane dehydrators. Both effectively remove moisture from the air, but do it in vastly different ways.
Desiccant dryers dry by passing the air through a container of a desiccant material. Dry air passes through the desiccant material while moisture adheres to the desiccant material. This process requires the desiccant to regenerate, which is the process of drying out the desiccant for further use. There are two ways the desiccant can be regenerated, with heat, and heatless. Regeneration with heat method uses an internal heating element to heat the desiccant material, which converts the moisture into steam that can be vented with pressurized dry air. Heatless regeneration uses purely the dry pressurized air to dry the desiccant.
Membrane dehydrators use a permeable membrane that will allow water to pass through, but not the larger oxygen and nitrogen molecules which is the prevalent molecule in air. The pressure would push the water molecules through the membrane while retaining the dry air.
Membrane dehydrators require less maintenance, but require higher pressure and cannot reach as low dew point as a desiccant system. A desiccant system can dry air to a lower dew point and requires less pressure, but needs to have it’s desiccant canisters replaced every 3 to 5 years, or more depending on use.
Both these methods of dehydration are applicable for waveguide dehydration system. It is important to assess your systems requirements and environmental conditions before selecting a proper dehydration unit. Please feel free to contact Environmental Technology or any of our partners here.
The overall purpose of the dehydrator is to eliminate moisture in the waveguide of the transmitter. Moisture will affect the reflected energy and increase the Standing Wave Ratio (SWR) of the system.
Dehydrators deal with moisture in waveguides differently than systems pressurized with inert gasses.
In pressurized systems, the system is sealed and moisture is kept out by the same seal that keeps the gas in. If the pressurized system develops a leak the inert gas leaks out and moisture can then accumulate in the system. In most cases, these pressurized systems then need to be re-pressurized in order to find and repair the leak, then be evacuated with a vacuum pump and refilled with the inert gas. This can become a long and expensive process.
In comparison, a dehydrator supplied waveguide is constantly having the air in the waveguide replaced with desiccated air and its pressure is varying from the low set point to the target set point. This delta P is the operating pressure for the system.
The operating pressure (∆P) is determined by the wave guide’s manufacturer’s recommended max pressure and the lowest pressure the customer is comfortable with as a minimum to the system. The max pressure is generally dictated by the feed horn window material.
- Low pressure alarm – this is the level at which the unit will present an alarm. This needs to be lower than the low limit pressure
- Low Limit Pressure – this is the level that will cause the dehydrator to start the compressor to pressurize the system. This must be at least .1 PSI lower than the High Limit Target Pressure
- High Limit Target Pressure – this is the level that the compressor will be turned off at.
- High pressure alarm – this is the level at which the unit will present an alarm. This needs to be higher than the High Limit Target Pressure
Perfectly sealed systems are not only difficult to manufacture but impossible to maintain over time. For this reason, ETI strives for perfect seals but accepts very small leaks in the system as normal. Our maximum allowable leak rate on a new system is .04 psi per minute on a system pressurized at 7.5 PSI. With a dehydrator’s outlet completely blocked off this would translate to a leak downtime of 2.5 hours or more if there is a ∆P of 6 PSI between the low limit pressure and the high limit target pressure.
It should be noted that the leak downtime is dependent on the ∆P. For example, the same leak rate of .04 PSI will take 2.5 minutes when the ∆P is .1 PSI.
For this reason, it is important to understand the relationship between the ∆P, leak rate & duty cycle. To do this also requires an understanding of how the duty cycle is calculated and what it means.
The duty cycle is calculated by averaging the time of two compression cycles using the time the compressor is on divided by total time (time compressor on and time off between cycles). The on time is going to be affected by a number of variables but the two most important variables are the volume of the waveguide and the flow rate of the compressor.
There is no hard and fast rule as to what duty cycle you should have on your dehydrator; it is entirely up to the customer to determine what is best for their application. In doing so it should be considered that once set, a change in the duty cycle indicates a change in the system/ waveguide. Setting the duty cycle alarm to approximately two times the selected duty cycle will allow the system to give the customer an alarm indicating a problem with the system.
Setting the duty cycle is accomplished by changing the waveguide bleed (normally mounted on or near the feed horn) to allow a constant managed leak of the system.
Netcom compressors have a flow rate of 10 liters per min so for small systems (1l or less) you are looking at only a few seconds of compressor time for a complete fill and fractions of a second for satisfying the ∆P requirements for operating pressure.
For these reasons, it is possible to have a NETCOM pressurizing a small system with a very small ∆P that will run the compressor every 10 to 15 seconds for a period of a fraction of a second. At first, this may appear to be an internal leak on the NETCOM but looking at the duty cycle and alarms you will be able to determine that the N ETCOM is simply working normally at a 5% duty cycle.
It would be advisable to reduce the duty cycle to as low as 1% for small systems in order to increase the time between compression cycles. This will also allow the casual observer to feel the system is operating normally without internal leaks or issues.
Another way to accomplish this is, of course, to increase the ∆P on the system slightly if the system will allow it. Again the limiting factor is the feed horn window max pressure limitations.
As an example:
If a system is initially set to a 1% duty cycle and the duty cycle alarm is set for 2% and after several months of operation the duty cycle alarm is indicated the operator has a number of options. He can start looking for the leak, find and fix it immediately or determine that the leak is small enough to not warrant immediate action because there has been no effect on the SWR of the system. The dehydrator has compensated for the leak with increased duty cycle. At this point, the operator may bump the duty cycle alarm up to 3%, report the issue and put it on the agenda for future maintenance on a remote site.
Comparing the above example to an inert gas pressurized system the leak would leave the system open to atmosphere and SWR would be affected necessitating an immediate repair.
Heat-trace is used in many aspects of everyday modern life that mostly goes unnoticed. One main example of this is the ability to access hot water quickly from any faucet in a large building no matter how far from the water heater it is. This is a function of a building’s Hot Water Maintenance system. heat-trace is just part of a comprehensive Hot Water Maintenance system. Other components of a Hot Water Maintenance are the water heater, hot water storage tanks, a circulation loop and a pressure release.
Hot Water Maintenance is important for many reasons, one of the most important reasons is to sanitize. Hot water helps to prevent diseases, like Legionnaires Disease by killing the bacteria that causes it and preventing it from multiplying within the pipes. Water that is too hot can lead to injury. It is important to have the temperature set within a safe range. Keeping the water hot throughout the pipes will also reduce water and energy waste by not having to run the water before reaching the hot water.
Heat-Trace systems consist of a heat cable (heat tape) and control. There are two types of heat cable, self-regulating and constant wattage. Self-regulating cable does what it says, it regulates itself to an extent. It does this with a special conductive material core between two bus wires. The core’s conductive nature varies with temperature, the cooler it gets the more conductive it becomes which increases the heat the cable gives off, the warmer it gets the less conductive it becomes resulting in the cable giving off less heat. Constant wattage heat cable provides a uniform distribution of wattage, resulting in uniform heating along the whole cable. Self-regulating cable will save energy, where constant wattage cable will heat in a more uniform precise way. Both self-regulating and constant wattage heat cable require a heat-trace control unit to regulate the temperature and monitor and alarm for errors.
Hot Water Maintenance systems are a hardly noticed element of our everyday lives that make our modern lifestyle possible. Heat-trace is a critical component of these systems, keeping the water hot within the pipes. Next time you are in a building pay attention to the hot water and think about what makes that possible.
ENVIRONMENTAL TECHNOLOGY’S HEAT-TRACE CONTROLS
Due to the high sensitivity of ground-fault-current detection circuits, it is possible that excessive line noise on the power source wiring can cause an alarm. This can occur in the form of a ground-fault alarm, a stuck-relay alarm, or a ground-fault circuit alarm.
This type of alarm can be caused by switching high-power loads, inductive loads, or any excessive arcing during operation of a contactor that is on the same circuit branch. It may also be caused by extreme levels of RFI (radio-frequency interference) in the area.
1. Use a separate circuit for the heat control
We recommend providing a separate circuit for the heat control, which is not shared with other equipment. In particular, any equipment that is electrically noisy needs to be on a different circuit branch and installed a safe distance away.
2. Use an external noise filter
The controller’s immunity to excessive conducted noise from contactors, inductive loads, and other sources of RF interference can be increased with an external noise filter. A simple way to provide additional filtering is to route the power supply cable through a ferrite toroid ring, with as many turns as possible. This will further attenuate the conducted RF noise.
One device that works well is the Palomar Engineering Ferrite Toroid Ring model F240-77. This is 1.4” ID and 2.4” OD, material type 77(Figure 1). There are larger sizes and other suppliers of these which also can work. We purchased our Ferrite Toroid Ring from here, but they can also be purchased at many electronic supply companies or on amazon.com.
This should be installed on the power line (source) cable to the controller (e.g. GPT or FPT), and placed near the controller’s housing (Figure 2). If the controller is fitted with conduit for the wiring to the power panel, the toroid can be placed just inside the power panel, at the end of the conduit (Figure 3). Three turns of the entire cable through the toroid are recommended; if more can be fit that will work better – the attenuation of noise is proportional to the square of the number of turns. A larger toroid can be used to accommodate more turns of the wire.
3. Adjust the ground fault threshold
In some situations, the ground fault threshold can be increased, and this will improve the noise immunity. On the GPT 130 and GPT 230, the ground-fault alarm current threshold can be adjusted from 1 mA to 300 mA, and the default setting is 30 mA. A higher setting will be more tolerant of electrical noise on the power line.
This past July Environmental Technology released its new line of microprocessor-based heat-trace controls, replacing its already successful SST line which has been a trusted industry standard since 2011. The new GPT and FPT heat-trace controls were created with input from leaders in the heat-trace industry to best fit their present and future needs.
Environmental Technology was founded in 1968 and is internationally recognized for their work in heat-trace, snow & ice melt and waveguide dehydrators. In 2015 the company founder and lead engineer Thaddeus Jones stepped down from day to day activity, leaving new products and engineering to the next generation of ETI leadership. The GPT and FPT line of heat-trace is the first major release under the new leadership.
The previous SST line of heat-trace has been well trusted and can be found on many prominent structures throughout North America where they will function properly for years to come. Environmental Technology will be discontinuing the SST line in late 2017 to make way for their new GPT and FPT heat-trace controls.
The GPT 130 is a single-point microprocessor-based general purpose heat-trace control with a temperature setpoint range of -99.9 °F to 999 °F (-73.3 °C to 537.7 °C) and advanced monitoring and alarms. It is designed for applications which require Ground–Fault Equipment Protection (GFEP). Ideal uses include freeze protection, hot water temperature maintenance, grease line trace, tank heating, and other temperature monitoring and control applications. The GPT 130 and its heater load can operate with an available line voltage source of 100 – 277 V ac. The controller and heater load share the same supply connection. The internal load contactor is rated to switch up to 30 A resistive. The Integral GFEP provides safety in compliance with national and local electrical codes. The unit’s housing is a NEMA 4X IP66 weather–resistant enclosure for enhanced durability.
The FPT 130 is a is a single-point microprocessor-based freeze protection heat-trace control with temperature setpoints of 30 °F, 38 °F, 45 °F, and 50 °F (-1.1 °C, 3.3 °C, 7.2 °C and 10 °C). It is designed for applications which require Ground–Fault Equipment Protection (GFEP). Ideal uses include freeze protection, and other temperature monitoring and control applications. The FPT 130 and its heater load can be powered with an available line voltage source of 100 – 277 V ac. The controller and heater load share the same supply connection. The internal load contactor is rated to switch up to 30 A resistive. The Integral GFEP provides safety in compliance with national and local electrical codes. The unit’s housing is a NEMA 4X IP66 weather–resistant enclosure for enhanced durability.
The GPT 230 is a dual-point microprocessor-based freeze protection heat-trace control that can control two channels with temperature setpoint ranges of -99.9 °F to 999 °F (-73.3 °C to 537.7 °C) and advanced monitoring and alarms. It is designed for applications which require two independent heater–control Channels with Ground–Fault Equipment Protection (GFEP). Ideal uses include freeze protection, hot water temperature maintenance, grease line trace, tank heating, and other temperature monitoring and control applications. The GPT 230 and its heater load can be powered with an available line voltage source of 100 – 277 V ac. The controller and heater load are powered from the same supply connection. The two internal load contactors are rated to switch up to 30 A resistive. The adjustable GFEP function provides additional safety and compliance with national and local electrical codes. The unit’s housing is a NEMA 4X IP66 weather–resistant enclosure for enhanced durability.
This new line of heat-trace controls will be the industry standard by providing reliable temperature control and comprehensive monitoring and alarms. Please visit networketi.com for more information about this or any of our other products.
The GPT unit comes with a thermistor (two thermistors with the GPT 230) but is also compatible a 2-, 3-, or 4-wire RTD sensor. The diagram illustrates the correct wiring and DIP switch configuration for each temperature sensor wiring scheme. It is important that you also navigate to the Sensor Type screen and select the type of sensor being used. * The GPT comes set up for use with the provided Thermister sensor.
The provided thermistor sensor will work for heat-trace applications where the operating range is between -40°F and 230°F (-40°C and 110°C). For applications that require a larger temperature range an RTD sensor is needed. With an RTD sensor and the GPT 130 or GPT 230 you can accurately monitor and control for temperatures from -99.9°F to 999°F (-73.3°C to 537.7°C). For more information about installing a 2-, 3-, or 4-wire RTD sensor or the provided thermistor consult the GPT 130 or GPT 230 manual or installation sheet.
The difference is the step down transformer that provides the power for the internal circuitry. On the 277 single phase the transformer is 277 VAC to 24 VAC and you will note that its primary winding is connected to the top and middle poles on the contactor.
On the 277/480 three phase unit the transformer is 480VAC to 24VAC and the primary winding is connected to the top and bottom poles on the contactor.
Consult a professional and or your electric provider to determine what configuration is needed.
The APS-C series systems are designed to turn on and off, as the weather requires heat to deal with snow or icing conditions. Although a thermostatic dry contact switch can be used to override the system on for temperature only, is not recommended since it will reduce the efficiency of the system. Running the heaters on cold days that do not have snowfall will not hurt anything but your budget.
If you must do so choose a thermostat with dry contacts that close when the temperature is below 40F and connect it to the override-on terminals of the EMC section of the Class 2 terminal block.
No, using external contactors will cause the GFEP circuit on the APS-4C to detect the inductive load of the contactors coil as ground fault and alarm the system every time the contactor is turned on. In order to increase the size of the application, a SC-40C satellite control can be used with the APS-4C without triggering the ground fault protection.
The APS-3C is designed without an internal GREP circuit so it will work with external contactors or direct heater loads. In both of these applications you must provide a GFEP breaker to power the heater circuit.
A flashing supply light indicates a missing or broken High-Temperature Limit sensor. This sensor is required to make the APS-C series controller to work. It is required on all of the APS-C series controllers.
The sensor is not polarized and must be connected to pins 10 and 11. Refer to figure 22 in the manual. If the Class two terminals are black with screw connections problems can occur when the screws are over tightened.
Above illustrates the terminal connections for the High Temperature sensor (thermistor) for the APS-4C, APS-3C, and the SC-40C Snow Switch Control Panels.